Jack Dorsey Launches App to Monitor Sun Exposure
▼ Summary
– Jack Dorsey released a new app called Sun Day, which tracks UV exposure and Vitamin D intake, following his recent launch of the messaging app Bitchat.
– Sun Day is currently available on iOS via TestFlight, and its code is open-source on GitHub for public use.
– Dorsey developed the app using an open-source coding tool called Goose, diverging from more common developer tools like Cursor or Claude Code.
– The app provides UV Index data, weather details, and personalized sun exposure recommendations based on skin type and clothing.
– Sun Day calculates daily Vitamin D intake by tracking UV exposure sessions and displays the results after each session.
Twitter co-founder Jack Dorsey has unveiled his latest tech venture, a sunlight tracking app designed to help users monitor UV exposure and vitamin D levels. The iOS application, named Sun Day, joins his growing portfolio of experimental projects following the recent launch of Bluetooth messaging platform Bitchat.
Currently available through TestFlight with its source code publicly accessible on GitHub, Sun Day provides real-time UV index data alongside environmental factors like cloud coverage and daylight hours. Users input personal details including skin type and clothing coverage, allowing the app to calculate safe sun exposure durations before skin damage occurs.
Dorsey developed the tool using Goose, an open-source coding platform, diverging from more mainstream developer environments. The minimalist interface features a single “Track UV Exposure” button to initiate monitoring sessions. After each session, the app displays accumulated vitamin D intake alongside daily totals, a feature targeting health-conscious individuals seeking data-driven sun habits.
While similar to existing weather and wellness apps, Sun Day’s niche focus on solar radiation metrics positions it as a specialized tool rather than a broad health platform. Its release continues Dorsey’s pattern of launching unconventional digital experiments since stepping back from Twitter’s leadership. The app’s open-source nature invites developer collaboration, potentially expanding its functionality beyond its current beta capabilities.
Image Credit: TechCrunch
(Source: TechCrunch)
